Jim
most likely blown power supply ... I seen it before. Just the small surge of unplugging then bang nothing. Usually happens when the power supply has been on its way out for some time. I am assuming however that the outlet is good and the power cord is full seated which I am sure you already checked. One other thing is check the back of your PC. on my Dell is a power on off that is separate from the push button on off in the front. Sometimes this happens on mine at the office and I switch it on and off in the back then push the button and it takes off

Dan